The figure presents the trajectories of six vehicles within a time-space domain. The number in the parentheses represents a unique identification of each vehicle.


The mean speed (in km/hr) of the vehicles in the entire time-space domain is ____________ (rounded off to the nearest integer).

A bird is resting on a point P at a height of 8 m above the Mean Sea Level (MSL). Upon hearing a loud noise, the bird flies parallel to the ground surface and reaches a point Q which is located at a height of 3 m above MSL. The ground surface has a falling gradient of 1 in 2. Ignoring the effects of curvature and refraction, the horizontal distance (in meters) between points P and Q is _______________ (in integer).

A parabolic vertical crest curve connects two road segments with grades +1.0% and $$-$$2.0%. If a 200 m stopping sight distance is needed for a driver at a height of 1.2 m to avoid an obstacle of height 0.15 m, then the minimum curve length should be _________ m. (round off to the nearest integer)